Micromechanical yaw-rate sensors are used in the automotive field, for example in ESP systems, for rollover sensing, or for navigation purposes. The object of the yaw-rate sensor is the correct measurement of the automobile movement around a rotational axis.
A conventional micromechanical yaw-rate sensor has an oscillating body, which extends in an x-y plane and is set into a linear oscillation along a spatial axis (e.g., x-axis) lying in this plane. In the event of a rotation around a rotational axis (z-axis) which is perpendicular to the plane, the Coriolis force causes a displacement of the oscillating body in a direction (y-axis) which is in the plane perpendicular to the oscillation axis (x-axis). This displacement may be capacitively detected and analyzed with the aid of measuring electrodes. In the case of this yaw-rate sensor, the rotational axis is perpendicular to the plane of the oscillating body (“out of plane”). Such a yaw-rate sensor is described, for example, in German Patent Application No. DE 10 2006 047 135 A1.
A further conventional micromechanical yaw-rate sensor has an oscillating body, which extends in the x-y plane and is set into a rotating oscillation around a rotational axis (z-axis) perpendicular to this plane. A rotation of the yaw-rate sensor around the x-axis or the y-axis causes tilting of the sensor. This tilting may be capacitively detected and analyzed with the aid of measuring electrodes. In the case of this yaw-rate sensor, the detected rotational axis is in the plane of the oscillating body (“in plane”). Such a sensor, which may detect a rotation around up to two rotational axes, is described, for example, in German Patent Application No. DE 10 2006 052 522 A1.
For many applications, however, it is insufficient to detect the rotation around two rotational axes. Rather, the movement of a body, such as a motor vehicle, is described by six degrees of freedom, namely by the movement along the three spatial axes and the rotation around the three spatial axes. There is already a demand for automobile sensor systems which detect all three yaw rate axes, namely rotations around the yaw axis for the ESP, rotations around the roll axis for rollover detection, and rotations around a horizontal axis perpendicular to these axes for detecting pitch movements.